[webcrypto] Make operations run on worker threads.

content/child/webcrypto/jwk.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_CHILD_WEBCRYPTO_JWK_H_
 #define CONTENT_CHILD_WEBCRYPTO_JWK_H_
 
+#include <vector>
+
+#include "base/basictypes.h"
 #include "third_party/WebKit/public/platform/WebArrayBuffer.h"
 #include "third_party/WebKit/public/platform/WebCrypto.h"
 #include "third_party/WebKit/public/platform/WebCryptoAlgorithmParams.h"
 
 namespace content {
 
 namespace webcrypto {
 
 class CryptoData;
 class Status;
 
 Status ImportKeyJwk(const CryptoData& key_data,
                     const blink::WebCryptoAlgorithm& algorithm,
                     bool extractable,
                     blink::WebCryptoKeyUsageMask usage_mask,
                     blink::WebCryptoKey* key);
 
-Status ExportKeyJwk(const blink::WebCryptoKey& key,
-                    blink::WebArrayBuffer* buffer);
+Status ExportKeyJwk(const blink::WebCryptoKey& key, std::vector<uint8>* buffer);
 
 }  // namespace webcrypto
 
 }  // namespace content
 
 #endif  // CONTENT_CHILD_WEBCRYPTO_JWK_H_